This invention lies in the field of truck body liners, that is, apparatus for pushing and pulling at selected points on the frame of a truck or heavy vehicle, so as to straighten frames, and bend parts as necessary, to properly line up the truck substructure.
More particularly this invention is directed to an apparatus for electrohydraulically carrying out all of the operations necessary to rapidly set a plurality of hydraulic push/pull devices, or robots, so as to straighten a crumpled truck frame.
Reference has been made to U.S. Pat. No. 3,888,100 which describes improved apparatus for rapidly and conveniently exerting hydraulic forces on an automobile the nominal forces required to straighten an automobile frame, many simplifications can be made in the mechanism, frame, many simplifications can be made in the mechanism, whereby cables or chains can be used, to pull around rollers or sheaves as required. However, when the extremely large forces required to straighten a heavy truck frame are considered, chains cannot be used, since if they are to withstand the tremendous forces exerted, they would be inordinately heavy, and difficult to use. Consequently, there has not been a suitable apparatus shown which can handle the forces required to straighten heavy truck frames, based upon the known art of apparatus for straightening the simpler lighter frames of automobiles and other small motor vehicles.
It is therefore an important object of this invention to provide an electrohydraulically controlled apparatus for exerting very large forces on a heavy vehicle frame, so as to provide a straightening and lining of the frame.
It is another important object of this invention to provide the pushing and pulling mechanisms that exert the selected forces at selected points on the frame, in the form of small hydraulic cranes which are adapted to run along tracks, on rollers, so as to be easily positioned at the proper point along the frame of the truck, and to be directed in any selected angle by swivel means. Suitable ball bearing means are provided so as to support the crane in rotation about a vertical axis, so that it can be used for lifting heavy parts of the vehicle such as tires, wheels, etc. and moving them along the tracks or swinging them laterally away from the vehicle.
It is a still further object to provide means by which the ball bearing means which is used to swivel the crane, to provide freedom of operation so long as the load on the crane is within the load limits of the bearing, and then to protect the bearings by exerting additional restraint means exterior of the bearing when the load is greater than the load capability of the bearing.